{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T16:21:21Z","timestamp":1792081281481,"version":"4.4.0"},"reference-count":31,"publisher":"National Academy of Sciences","issue":"15","license":[{"start":{"date-parts":[[2024,4,2]],"date-time":"2024-04-02T00:00:00Z","timestamp":1712016000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["EAR 0207721"],"award-info":[{"award-number":["EAR 0207721"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["EAR 0544093"],"award-info":[{"award-number":["EAR 0544093"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["EAR 0208377"],"award-info":[{"award-number":["EAR 0208377"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000001","name":"National Science Foundation","doi-asserted-by":"publisher","award":["EAR 0544565"],"award-info":[{"award-number":["EAR 0544565"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2024,4,9]]},"abstract":"<jats:p>\n                    The axial columns of the earliest limbed vertebrates show distinct patterns of regionalization as compared to early tetrapodomorphs. Included among their novel features are sacral ribs, which provide linkage between the vertebral column and pelvis, contributing to body support and propulsion by the hindlimb. Data on the axial skeletons of the closest relatives of limbed vertebrates are sparce, with key features of specimens potentially covered by matrix. Therefore, it is unclear in what sequence and under what functional context specializations in the axial skeletons of tetrapods arose. Here, we describe the axial skeleton of the elpistostegalian\n                    <jats:italic>Tiktaalik roseae<\/jats:italic>\n                    and show that transformations to the axial column for head mobility, body support, and pelvic fin buttressing evolved in finned vertebrates prior to the origin of limbs. No atlas\u2013axis complex is observed; however, an independent basioccipital\u2013exoccipital complex suggests increased mobility at the occipital vertebral junction. While the construction of vertebrae in\n                    <jats:italic>Tiktaalik<\/jats:italic>\n                    is similar to early tetrapodomorphs, its ribs possess a specialized sacral domain. Sacral ribs are expanded and ventrally curved, indicating likely attachment to the expanded iliac blade of the pelvis by ligamentous connection. Thus, the origin of novel rib types preceded major alterations to trunk vertebrae, and linkage between pelvic fins and axial column preceded the origin of limbs. These data reveal an unexpected combination of post-cranial skeletal characters, informing hypotheses of body posture and movement in the closest relatives of limbed vertebrates.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2316106121","type":"journal-article","created":{"date-parts":[[2024,4,2]],"date-time":"2024-04-02T14:40:21Z","timestamp":1712068821000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":13,"title":["The axial skeleton of\n                    <i>Tiktaalik roseae<\/i>"],"prefix":"10.1073","volume":"121","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7965-5901","authenticated-orcid":false,"given":"Thomas A.","family":"Stewart","sequence":"first","affiliation":[{"name":"Department of Biology, The Pennsylvania State University, State College, PA 16802"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5837-4361","authenticated-orcid":false,"given":"Justin B.","family":"Lemberg","sequence":"additional","affiliation":[{"name":"Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4898-3571","authenticated-orcid":false,"given":"Emily J.","family":"Hillan","sequence":"additional","affiliation":[{"name":"Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isaac","family":"Magallanes","sequence":"additional","affiliation":[{"name":"Committee on Evolutionary Biology, The University of Chicago, Chicago, IL 60637"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward B.","family":"Daeschler","sequence":"additional","affiliation":[{"name":"Department of Vertebrate Zoology, Academy of Natural Sciences of Drexel University, Philadelphia, PA 19103"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Neil H.","family":"Shubin","sequence":"additional","affiliation":[{"name":"Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637"},{"name":"Committee on Evolutionary Biology, The University of Chicago, Chicago, IL 60637"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2024,4,2]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1017\/S0263593300006787"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature03893"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature11825"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1502-3931.1996.tb01839.x"},{"key":"e_1_3_4_5_2","volume-title":"The Vertebrate Body","author":"Romer A. S.","year":"1977","unstructured":"A. S. Romer, T. S. Parsons, The Vertebrate Body (Saunders, 1977)."},{"key":"e_1_3_4_6_2","first-page":"255","volume-title":"The terrestrial environment and the origin of land vertebrates","author":"Rackoff J. S.","year":"1980","unstructured":"J. S. Rackoff, \u201cThe origin of the tetrapod limb and the ancestry of Tetrapods\u201d in The terrestrial environment and the origin of land vertebrates, A. L. Panchen, Ed. 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Trueb, Eds. (Cornell University Press, Ithaca, 1991), pp. 68\u2013109."},{"key":"e_1_3_4_14_2","first-page":"735","article-title":"The evolution of vertebrae in rhipidistians","volume":"76","author":"Vorobyeva E. I.","year":"1986","unstructured":"E. I. Vorobyeva, A. A. Tsessarskii, The evolution of vertebrae in rhipidistians. Zhurnal Obshchet Biol. 76, 735\u2013747 (1986).","journal-title":"Zhurnal Obshchet Biol."},{"key":"e_1_3_4_15_2","first-page":"293","article-title":"The panderichthyid fish Elpistostege: A close relative of tetrapods?","volume":"28","author":"Schultze H.","year":"1985","unstructured":"H. Schultze, M. Arsenault, The panderichthyid fish Elpistostege: A close relative of tetrapods? 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A. Stewart Project: CT data for The axial skeleton of Tiktaalik roseae. 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